The narrative technique used by the author is setting.
Indeed, this text is a description of the situation the main character finds himself in. We are given information about:
- the time of day ("early afternoon"),
- the action ("riding" a "train"),
- the other characters ("migrants," "villagers"),
- the surroundings ("trash by the rails," "adobe and cinder-block homes")
- and even—or especially—the climate ("105 degrees").
This sets the context for the upcoming twists and turns of the story.
This technique supports the author's purpose by creating a sense of oppression.
The ways the protagonist's situation is described makes the oppressive feeling almost palpable, with phrases "warm ... smoke," "searing stench," "heat," and the repetition of the word "burn." It gives the impression that the heat is felt through various different senses:
- touch, with the burning palms;
- sight, with the diesel smoke;
- and smell, with the very hot stench.
The idea of oppression is further conveyed by several allusions to what Enrique and other migrants long for to escape this crushing heat: they envy "villagers cooling themselves" or "doz[ing] in hammocks slung in shady spots," and the train cars even remind them of "bobbing ice cubes."